High-Density Reconstituted Plant Sheet

ABSTRACT

The invention relates to a reconstituted plant sheet suitable for devices for heating tobacco without burning it, said reconstituted plant sheet having a high density.

TECHNICAL FIELD

The present disclosure relates to the field of devices for heating tobacco without burning it and the subject thereof is a reconstituted plant sheet obtained by means of a high-density papermaking process.

CONTEXT OF THE INVENTION

A large number of devices for heating tobacco without burning it have been developed in order to avoid the formation of the harmful constituents during tobacco combustion. By way of example, mention may be made of the applications published under numbers WO 2016/026810 and WO 2016/207407 which describe such devices. In these devices, the tobacco is heated at a temperature below the combustion temperature without being burnt, which leads to the formation of an aerosol. The aerosol generated during the heating of the tobacco replaces the cigarette smoke, and has advantageous organoleptic properties when it is inhaled by the user. This thus allows the user to inhale nicotine and the tobacco aromas while at the same time very significantly reducing said user's exposure to the harmful constituents.

In order for the user to adopt these heating devices, it is important for the experience obtained with said devices to be as close as possible to the experience obtained with a conventional cigarette, that is to say an amount of nicotine equivalent to a conventional cigarette and satisfactory organoleptic properties for each puff.

Conventional tobacco is not suitable for such devices since it does not make it possible for the user to obtain a satisfactory experience, in particular it does not make it possible to easily generate a sufficient amount of aerosol having advantageous organoleptic properties.

Reconstituted tobacco is more suitable for these heating devices, since it makes it possible to generate a large amount of aerosol having advantageous organoleptic properties.

However, the reconstituted tobacco must comprise a minimal amount of aerosol-generating agent to generate a satisfactory amount of aerosol. For instance the reconstituted tobacco disclosed in U.S. Pat. No. 3,145,717 comprises only 3% by weight of solids of aerosol-generating agent. The amount of aerosol generated by this reconstituted tobacco and the nicotine transfer rate of this reconstituted tobacco in a heating device are too low to be satisfactory.

Therefore, it is advisable to improve the organoleptic properties of the aerosols formed at each puff and to further increase the nicotine transfer rate so that the experience obtained with the heating devices is even closer to the experience obtained with a conventional cigarette.

SUMMARY

It is thus to the credit of the inventors to have found that it is possible to meet these needs by means of a reconstituted plant sheet comprising:

a fibrous support comprising refined plant fibers,

an aerosol-generating agent, and

a plant extract,

-   characterized in that -   the density of the reconstituted plant sheet is greater than or     equal to 0.6 g/cm³, and -   the total content by weight of solids of the aerosol-generating     agent is between 10% and 29%.

Advantageously, the reconstituted plant sheet according to the invention has a nicotine transfer rate greater than a reconstituted plant sheet of lower density.

Furthermore, at each puff, the reconstituted plant sheet according to the invention advantageously forms an aerosol, the organoleptic properties of which are improved compared with an aerosol formed by a reconstituted plant sheet of lower density.

A second subject of the invention is a process for producing a reconstituted plant sheet according to the invention, comprising the following steps:

-   a) passing the fibers through a papermaking machine so as to     constitute a fibrous support, -   b) bringing an aerosol-generating agent and a plant extract into     contact with the fibrous support so as to obtain a wet reconstituted     plant sheet, and -   c) drying the wet reconstituted plant sheet.

A third subject of the invention is a use of a reconstituted plant sheet according to the invention in a heating device, in particular a device for heating tobacco without burning it.

DESCRIPTION OF THE EMBODIMENTS

According to a first subject, the invention relates to a reconstituted plant sheet comprising:

a fibrous support comprising refined plant fibers,

an aerosol-generating agent, and

a plant extract,

-   wherein the density of the reconstituted plant sheet is greater than     or equal to 0.6 g/cm³, and -   the total content by weight of solids of aerosol-generating agent is     between 10% and 29%.

Typically, the density of the reconstituted plant sheet may be between 0.62 g/cm³ and 1.50 g/cm³, in particular between 0.65 g/cm³ and 1 g/cm³, more particularly between 0.66 g/cm³ and 0.70 g/cm³.

Typically, the density of the reconstituted plant sheet is calculated by dividing its basis weight by its thickness.

To determine the basis weight of the plant sheet, the following method may be used:

-   a sample of 0.25 m² is cut out with a template (dimensions:     57.5×43.5 cm) at approximately 15 cm from the edge of the     reconstituted plant sheet to be analyzed. The sample is then folded     in four and placed on a hot plate so as to be dried thereon in order     to remove the water without removing the aerosol-generating agent. -   The dried sample is then weighed to determine the basis weight of     the plant sheet.

To determine the thickness of the plant sheet, the method described in standard NF EN ISO 534 (December 2011) suitable for the reconstituted plant sheets may be used:

the average thickness of the control parchment paper used to measure the thickness of the reconstituted plant sheet is measured (minimum of 6 measurements on a layer, on sites pinpointed on the paper),

the reconstituted plant sheet sample is placed between 2 thicknesses of parchment paper,

as soon as the probe of the micrometer has been put in place, there is a waiting period of 30 seconds before taking measurement (stabilization of the sample for thickness measurement),

a minimum of 6 measurements are taken at the sites pinpointed on the sheet of parchment paper,

the calculated thickness of the reconstituted plant sheet is the average of the overall thickness measured (reconstituted plant sheets +2 sheets of parchment paper) from which is subtracted 2 times the average thickness of the parchment paper.

Typically, the reconstituted plant sheet can have a basis weight of between 60 g/m² and 300 g/m², in particular between 80 g/m² and 250 g/m², most particularly between 90 g/m² and 200 g/m², even more particularly between 140 g/m² and 190 g/m².

Typically, the reconstituted plant sheet can have a thickness of between 100 μm and 450 μm, in particular between 120 μm and 375 μm, most particularly between 140 μm and 325 μm.

According to one particular embodiment, the reconstituted plant sheet can have a density of between 0.65 g/cm³ and 1 g/cm³, a basis weight of between 90 g/m² and 200 g/m² and a thickness of between 140 μm and 325 μm.

Those skilled in the art will know how to adjust the basis weight and the thickness of the reconstituted plant sheet to achieve the desired high density.

For the purposes of the present application, the term “fibrous support” denotes a base web comprising refined fibers of the plant, the base web typically being obtained by means of a papermaking process.

For the purposes of the present application, the term “refined fibers of the plant” denotes fibers of the plant which have undergone a refining step enabling fibrillation and/or cutting of the fibers of the plant. The refining step is conventionally carried out in a papermaking process, such as the papermaking process producing reconstituted papermaking tobacco. On the other hand, the refining step is not carried out in a process producing cast leaf reconstituted tobacco such as the one disclosed in EP 0 565 360 and WO 2012/164009.

For example, the refined fibers of the plant may have a degree Schopper-Riegler (° SR) of from 15° SR to 75° SR, in particular of from 20° SR to 65° SR, more particularly of from 25° SR to 55° SR.

Typically, the fibrous support may comprise refined fibers of one same plant or of several plants.

For the purpose of the present application, the term “aerosol-generating agent” denotes a compound which allows the formation of an aerosol when it is heated, for example in contact with hot air.

Let S_(AG) be the total content by weight of solids of the aerosol-generating agent included in the reconstituted plant sheet of the present invention. Typically, S_(AG) may be between 14% and 27%, more particularly between 16% and 25%.

The aerosol generated by a reconstituted plant sheet having a S_(AG) greater than the ranges mentioned above causes unwanted burning of the mouth and/or the throat (phenomenon known as “hot puff”).

Typically, the aerosol-generating agent may be a polyol, a non-polyol or a mixture thereof. Typically, a generating agent that is a polyol may be sorbitol, glycerol, propylene glycol, triethylene glycol or a mixture thereof. Typically, a generating agent that is a non-polyol may be lactic acid, glyceryl diacetate, glyceryl triacetate, triethyl citrate, isopropyl myristate or a mixture thereof.

According to one embodiment, the aerosol-generating agent is glycerol, propylene glycol, or a mixture of glycerol and propylene glycol, glycerol being preferred.

An aerosol is generated during heating of the reconstituted plant sheet of the invention. Advantageously, the plant extract which comprises aromatic compounds confers aromas from the plant on this aerosol. By simply changing reconstituted plant sheet, the user can easily vary the aromas of the aerosol generated by heating said reconstituted plant sheet.

For the purposes of the present application, the term “plant extract” denotes all of the water-soluble products of the plant. Advantageously, the plant extract comprises nicotine, and the compounds conferring organoleptic properties and/or therapeutic properties on the aerosol.

The organoleptic properties and the therapeutic properties of the aerosol formed by heating said reconstituted plant sheet may depend on the content by weight of solids of the plant extract included in the reconstituted plant sheet of the present invention.

The total content by weight of solids of the plant extract depends on the plant used and, more particularly, on the content of aromatic compounds or of compounds having therapeutic properties of the plant used.

Let S_(P) be the total content by weight of solids of the plant extract included in the reconstituted plant sheet of the present invention. Typically, S_(P) may be between 20% and 45%, in particular between 25% and 40%, more particularly between 27% and 36%.

To determine S_(P), use may be made of the following method: the reconstituted plant sheet to be analyzed is ground in order to achieve a particle size of less than or equal to 1 mm. The reconstituted plant sheet is then mixed with boiling water for 45 minutes in order to extract all of the plant extract. S_(P) is calculated by the difference between the dry weight of the sample of reconstituted plant sheet to be analyzed and the dry weight of the fibrous residue after extraction.

According to one embodiment, the sum of the total content by weight of the solids of plant extract and of the total content by weight of solids of aerosol-generating agent, S_(P)+S_(AG), may be between 40% and 70%, in particular between 45% and 65%, more particularly between 50% and 60%.

According to one embodiment, the ratio between the total content by weight of solids of plant extract and the total content by weight of solids of aerosol-generating agent, S_(P)/S_(AG), is between 1.0 and 2.0, in particular between 1.10 and 1.80, more particularly between 1.15 and 1.70.

Advantageously, the nicotine transfer rate is improved and the organoleptic properties of the aerosols formed are even more satisfactory when the reconstituted plant sheet according to the invention has an S_(P)/S_(AG) ratio in the ranges mentioned above.

According to one particular embodiment, the reconstituted plant sheet can have an S_(AG) of between 16% and 25%, an S_(P) of between 27% and 35%, and an S_(P)+S_(AG) of between 50% and 60%.

According to one particular embodiment, the reconstituted plant sheet can have a density of between 0.65 g/cm³ and 1 g/cm³, a basis weight of between 90 g/m² and 200 g/m² and a thickness of between 140 μm and 325 μm, an S_(AG) of between 16% and 25%, an S_(P) of between 27% and 35%, and an S_(P)+S_(AG) of between 50% and 60%.

The plant fibers and the plant extract can be independently obtained from a plant chosen from spore-producing plants, seed-producing plants or a mixture thereof. In particular, the plant may be a plant chosen from the tobacco plant, food plants, aromatic plants, fragrant plants, medicinal plants, plants of the family Cannabaceae, or a mixture thereof.

According to one particular embodiment, the plant is the tobacco plant.

If the plant is a medicinal plant, the aerosol generated by heating the reconstituted plant sheet may also have therapeutic properties so that the reconstituted plant sheet can be used for a therapeutic treatment.

Advantageously, a plant extract obtained from a plant mixture makes it possible to offer a broad panel of organoleptic properties and/or therapeutic properties. A plant mixture also makes it possible to counteract the unpleasant organoleptic properties of a plant of the mixture, for example a medicinal plant, with the pleasant organoleptic properties of another plant of the mixture, for example the tobacco plant, an aromatic plant or a fragrant plant.

Typically, the plant fibers can be obtained from a first plant and the plant extract can be obtained from a second plant. Indeed this is because the fibers of a plant may not have mechanical properties which allow the formation of a fibrous support, but the extract of this plant may confer desired organoleptic properties and/or therapeutic properties on the aerosol. Conversely, the fibers of a plant may have mechanical properties which allow the formation of a fibrous support, but the extract of this plant may not confer desired organoleptic properties and/or therapeutic properties on the aerosol.

Advantageously, mixing plants to obtain the plant fibers makes it possible to adjust the mechanical properties of the reconstituted plant sheet and/or the organoleptic or chemical properties of the aerosol.

When the plant is the tobacco plant, then the tobacco fibers and the tobacco extract can be obtained from any tobacco plant or tobacco type plant, for example Virginia tobacco, Burley tobacco, air-cured tobacco, dark air-cured tobacco, Orient tobacco, sun-cured tobacco, fire-cured tobacco, or a mixture thereof.

Typically, the food plants are garlic, coffee, ginger, licorice, rooibos, Stevia rebaudiana, tea, cacao tree, chamomile, mate, star anise, fennel, citronella.

Typically, the aromatic plants are basil, turmeric, clove, laurel, oregano, mint, rosemary, sage, thyme.

Typically, the fragrant plants are lavender, rose, eucalyptus.

Typically, the medicinal plants are those indicated in the document, list A of traditionally used medicinal plants (French pharmacopeia January 2016, published by the Agence Nationale de Sécurité du Medicament (ANSM) [French National Agency for Drug and Health Product Safety] or plants known to comprise compounds which have therapeutic properties. Typically, the medicinal plants listed are ginkgo, ginseng, sour cherry, peppermint, willow and red vine.

Typically, eucalyptus is among the medicinal plants known to comprise compounds which have therapeutic properties.

Typically, the plant fibers and the plant extract of the reconstituted plant sheet of the present invention may be derived from various plant parts, the plant parts being parts of the plant itself or the result of the processing of various plant parts. Typically, the plant parts may be whole parts of the plant or debris originating from threshing or mixing and shredding the plant parts.

Typically, the plant parts may be selected from the plant parts richest in aromatic compounds conferring on the aerosol its organoleptic properties. Typically, these parts may be the whole plant, the aerial plant parts, such as the flower bud, the branch bark, the stem bark, the leaves, the flower, the fruit and its peduncle, the seed, the petal, the flower head, or the underground parts, for example the bulb, the roots, the root bark, the rhizome, or a mixture thereof. The plant part may also be the result of the mechanical, chemical or mechanical-chemical processing of one or more plant parts, such as for example the shell protecting the cacao bean resulting from the bean dehulling process.

Typically, the tobacco plant parts may be the parts richest in aromatic compounds conferring on the aerosol its organoleptic properties. Typically, the tobacco plant parts may be the parenchyma (lamina) optionally with added stems of the tobacco plant. Typically, the tobacco plant parts may be the leaves of the tobacco plant or the debris originating from threshing or mixing and shredding the leaves and veins of the tobacco plant into scaferlati (cut tobacco).

Among the food plants, the garlic bulb, the coffee cherry, the star anise fruit, the rhizome of ginger, the licorice root and the leaves of rooibos, Stevia rebaudiana or tea may for example be selected as parts.

Among the aromatic plants, clove flower buds (the cloves), basil, laurel and sage leaves, mint, oregano, rosemary and thyme leaves and flower head, or the turmeric rhizome may for example be selected as parts.

Typically, among the fragrant plants, the lavender flower and flower head, or the rose flower bud and petals may be selected.

Among the medicinal plants listed in the French pharmacopeia, gingko leaf, the underground part of ginseng, the peduncle of the sour cherry fruit (cherry stalk), the leaves and flower head of peppermint, the stem bark and the leaves of willow, or the leaves of red vine may for example be selected.

According to one particular embodiment, the reconstituted plant sheet can have a density of between 0.65 g/cm³ and 1 g/cm³, a basis weight of between 90 g/m² and 200 g/m² and a thickness of between 140 μm and 325 μm, an S_(AG) of between 16% and 25%, an S_(P) of between 27% and 35%, and an S_(P)+S_(AG) of between 50% and 60% and the plant is the tobacco plant.

Typically, the content by weight of solids of the refined plant fibers included in the reconstituted plant sheet may be between 15% and 70%, in particular between 30% and 61%, more particularly between 40% and 57%.

Typically, the fibrous support of the reconstituted plant sheet may also comprise cellulose-based plant fibers.

Cellulose-based plant fibers are fibers obtained by means of a chemical or mechanical or thermomechanical cooking process, such as wood pulp, hemp, or annual plants such as flax for example. A mixture of these cellulose-based plant fibers may also be used.

Advantageously, these cellulose-based plant fibers can improve the mechanical strength properties of the reconstituted plant sheet.

Typically, the cellulose-based plant fibers can represent between 0.5% and 20%, in particular between 3% and 17.5%, more particularly between 5% and 15% by weight of solids of the reconstituted plant sheet.

According to a second subject, the invention relates to a process for producing a reconstituted plant sheet as defined above, comprising the following steps:

-   a) passing the refined plant fibers through a papermaking machine so     as to constitute a fibrous support, -   b) bringing an aerosol-generating agent and a plant extract into     contact with the fibrous support so as to obtain a wet reconstituted     plant sheet, and -   c) drying the wet reconstituted plant sheet.

According to the invention, the fibrous support is produced using a papermaking process. According to one preferred embodiment of the invention, a reconstituted plant sheet according to the invention is a reconstituted plant sheet that can be obtained by means of a papermaking process.

Typically, the fibrous support constituted during step a) may have a basis weight of between 25 g/m² and 150 g/m²; in particular, the minimum value of the basis weight may be 55 g/m², 60 g/m², 65 g/m², 70 g/m², 75 g/m².

Advantageously, a fibrous support, the basis weight of which is included in the ranges above, makes it possible to obtain the desired high density.

Typically, the fibrous support constituted during step a) may have a thickness of between 70 μm and 430 μm, in particular of between 100 μm and 350 μm, most particularly of between 120 μm and 300 μm.

The basis weight and the thickness of the fibrous support are typically measured by the same methods as the basis weight and the thickness of the reconstituted plant sheet described above.

According to one embodiment, the plant fibers of the fibrous support and the plant extract are obtained in accordance with the following steps:

-   d) mixing one or more plant parts with a solvent in order to extract     the plant extract from the plant fibers, -   e) separating the plant extract from the plant fibers.

The plant extract and the plant fibers are therefore typically obtained by means of a dissociation process. During step d), one or more plant parts are mixed with a solvent, for example in a digester, in order to extract the plant extract from the plant fibers. During step e), the plant extract is separated from the plant fibers, for example by passing through a screw press, in order to isolate and obtain, on the one hand, the plant fibers and, on the other hand, the plant extract.

Typically, the solvent may be an apolar solvent, an aprotic polar solvent, a protic polar solvent, or a mixture thereof, in particular the solvent may be methanol, dichloromethane, ethanol, acetone, butanol, water or a mixture thereof, more particularly the solvent is ethanol, acetone, water or a mixture thereof.

According to one particular embodiment, the solvent is an aqueous solvent, most particularly the solvent is water.

Those skilled in the art will know how to adapt the temperature of the solvent during step d) to the plant, to the plant part and to the plant parts to be treated. Typically, the temperature of the solvent during the treatment of a root or of a bark will be higher than the temperature of the solvent during the treatment of a leaf or a petal.

Typically, the temperature of the solvent during step d) may be between 10° C. and 100° C., in particular between 30° C. and 90° C., more particularly between 50° C. and 80° C.

According to the embodiment wherein the solvent is water and the plant is tobacco, the temperature of the water may typically be between 30° C. and 80° C. Typically, for the treatment of the stems of a tobacco plant, the temperature of the water may be between 50° C. and 80° C. Typically, for the treatment of the parenchyma of a tobacco plant, the temperature of the water may be between 30° C. and 70° C.

Typically, the plant fibers may be refined in a refiner and then passed through the papermaking machine so as to constitute the fibrous support.

Typically, the refined plant fibers may originate from various plants.

The fibers of each plant can be obtained separately according to the dissociation process described above. They can subsequently be mixed such that this mixture of fibers from various plants passes through the papermaking machine so as to constitute the fibrous support. It is also possible to obtain fibers from various plants together by bringing together one or more parts of the various plants and then subjecting them to the dissociation process described above. The temperature of the water will then be adapted to the plants to be treated and, in particular, to the plant requiring the highest temperature of the water for extracting the extract of this plant. This alternative embodiment is very advantageous since it makes it possible to obtain the fibers of the various plants without carrying out several dissociation processes in parallel.

Typically, the plant extract may be an extract of various plants.

The extract of various plants can be obtained by mixing various plant extracts obtained separately according to the dissociation process described above. It is also possible to obtain the extract of various plants by bringing together one or more parts of the various plants and then subjecting them to the dissociation process described above. The temperature of the water will then be adapted to the plants to be treated and, in particular, to the plant requiring the highest temperature of the water for extracting the extract of this water-soluble plant. This alternative embodiment is very advantageous since it makes it possible to obtain the extract of various plants without carrying out several processes in parallel. In these two situations, the extract of various plants is brought into contact with the fibrous support during step b).

Typically, various plant extracts, obtained according to the dissociation process described above, can also be brought into contact with the fibrous support separately during step b).

Typically, the plant extract can be concentrated before being brought into contact with the fibrous support during step b). A device such as a vacuum evaporation device can be used to concentrate the plant extract.

Typically, during step b), the plant extract and the aerosol-generating agent can be brought into contact with the fibrous support one after the other, or can be mixed so as to be brought into contact with the fibrous support together.

Typically, step b) of bringing the plant extract into contact can be carried out by impregnation or by spraying, in particular by impregnation. Typically, the impregnation can be carried out by means of a size press.

For example, in order to obtain the desired high density, it is possible to reduce the line pressure applied by the size press during step b). Typically, this line pressure during step b) is much lower than the line pressure applied by a size press used in conventional papermaking processes for producing reconstituted plant sheets, such as those described in applications FR 15 59081 and FR 17 57991.

In order to obtain the desired high density, it is advisable to also adapt the total amount of plant extract and of aerosol-generating agent used in step b) to the basis weight of the fibrous support.

Contrary to conventional papermaking processes for producing reconstituted plant sheets, which produce reconstituted plant sheets having a density of less than 0.6 g/cm³, and without wishing to be bound to any theory, the inventors are of the opinion that step b) of the process of the invention makes it possible to obtain the desired high density by allowing impregnation of the plant extract and of the aerosol-generating agent into the fibrous support. This specific impregnation makes it possible to obtain a homogeneous distribution of the plant extract and of the aerosol-generating agent in the fibrous support and to increase the nicotine transfer rate.

Typically, those skilled in the art will know how to adapt the operating conditions for carrying out the drying step c).

Typically, the drying step c) can be carried out by infrared ramp, American battery drying drums, hot-air drying in a tunnel drier, a vertical drier, a fluidized-bed drier, a pneumatic drier, in particular in a tunnel drier.

The reconstituted plant sheet of the invention may then be cut into sheets, leaves similar to strips of tobacco or rolled into a roll. Several sheets may be assembled in order to form a mixture of sheets.

The reconstituted plant sheet of the invention may be used in a device for heating tobacco without burning it.

Thus, according to a third subject, the invention relates to a use of a reconstituted plant sheet as defined above, in a heating device, in particular a device for heating tobacco without burning it.

For the purposes of the present invention, the term “device for heating tobacco without burning it” denotes any device which allows the formation of an aerosol intended to be inhaled by a consumer. The aerosol replaces the smoke, thus allowing the user to inhale the plant aromas while at the same time very significantly reducing his or her exposure to the harmful constituents.

Typically, a heating device comprises, in the direction of the air flow, an air inlet, a heating body, a lodging intended to put in place and hold the reconstituted plant sheet of the invention comprising the generating agent, and an air outlet intended to be introduced into the mouth of the user. The air inlet, the heating body, the lodging and the air outlet are typically connected at least fluidically to one another.

Typically, when the heating device is used, air is sucked into the heating device via the air inlet by the user; the air sucked in then passes through the heated portion so as to obtain heated air; on contact with the reconstituted plant sheet of the invention comprising the generating agent, held in the lodging, an aerosol is formed by the heated air and is then inhaled by the user. If the plant is a medicinal plant, then the aerosol formed has therapeutic properties.

Furthermore, by virtue of the heating device, there is no combustion of the sheet. The user can therefore take advantage of the organoleptic properties of the plant, and optionally of the tobacco, while at the same time very significantly reducing their exposure to the harmful constituents.

EXAMPLES

Reconstituted Tobacco Sheet 1 in Accordance with the Invention

A mixture of scraps and stems of tobacco of Virginia type is brought into contact with water at 65° C. with stirring for 45 minutes. The tobacco extract is separated from the fibrous portion by mechanical pressing. The tobacco extract is concentrated under vacuum to a solids concentration of 54%. Glycerol, as aerosol-generating agent, is added to the concentrated tobacco extract.

The tobacco fibers are refined to have a degree Schopper-Riegler of 55° SR and then passed to a laboratory papermaking machine so as to constitute a fibrous support which has a basis weight of approximately 77 g/m².

The concentrated tobacco extract comprising glycerol is brought into contact with the fibrous support by impregnation in a size press to produce the reconstituted tobacco sheet in order to obtain an S_(P) of 27.3%, an S_(AG) of 23.7% and a sum S_(AG)+S_(P) of 51% in the reconstituted tobacco sheet produced.

This sheet has a density of 0.68 g/cm³, a basis weight of 145 g/m² and a thickness of 212 μm.

Reconstituted Tobacco Sheet 2 in Accordance with the Invention

Another reconstituted tobacco sheet is produced according to the method described above, the differences being that: it is a mixture of strips and stems of tobacco of Virginia type that is used, the degree Schopper-Riegler is 25° SR, the basis weight of the fibrous support is approximately 78 g/m², S_(AG) is 20.7%, S_(P) is 30.8% and the sum S_(AG)+S_(P) is equal to 51.5%.

This sheet has a density of 0.69 g/cm³, a basis weight of 156 g/m² and a thickness of 226 μm.

Reconstituted Tobacco Sheet 3 in Accordance with the Invention

Another reconstituted tobacco sheet is produced according to the method described above, the differences being that: it is a mixture of strips and stems of tobacco of Virginia type that is used, the degree Schopper-Riegler is 25° SR, the basis weight of the fibrous support is approximately 63 g/m², S_(AG) is 21.1%, S_(P) is 35.4% and the sum S_(AG)+S_(p) is equal to 56.5%.

This sheet has a density of 0.61 g/cm³, a basis weight of 129 g/m² and a thickness of 186 μm.

Reconstituted Tobacco Sheet Not in Accordance with the Invention

A reconstituted tobacco sheet not in accordance with the invention is produced according to a procedure similar to that described above, the differences being that the basis weight of the fibrous support is 57 g/m², that S_(P) is 34.1%, S_(AG) is 14.9% and the sum S_(AG)+S_(P) is 43%.

This reconstituted tobacco sheet has a density of less than 0.6 g/cm³, a basis weight of 95 g/m² and a thickness of 166 μm.

Nicotine Transfer Rate

The nicotine transfer rate of the reconstituted tobacco sheet 1 in accordance with the invention and of the reconstituted tobacco sheet not in accordance with the invention is determined with a heating system of glo™ type and according to the following protocol.

The nicotine transfer rate in a reconstituted tobacco sheet is calculated by dividing the nicotine content in the aerosol, generated by heating said reconstituted tobacco sheet, by the nicotine content in said reconstituted tobacco sheet.

The nicotine content in the aerosol generated by heating the reconstituted tobacco sheet is determined in the following way:

-   the tobacco is emptied out of commercial Dunhill stick bought in     Italy in August 2018 tubes for glo™ and said tubes are filled with     scaferlati (cut tobacco) of the sheet tested, with a weight of     tobacco of 260 mg/stick and a drawing resistance of 70+/−3 mm of     water column, -   an aerosol is generated via a Borgwaldt RM04 smoking machine on     which the filled sticks have been installed (by applying the     procedure for use supplied with the glo™ heating system), -   the material of the aerosol is collected on a 40 mm Cambridge     filter. It is then dissolved in methanol, -   the nicotine content in the aerosol is assayed after separation by     gas chromatography and assaying by FID relative to n-heptadecane     (used as standard). The nicotine content of the aerosol is measured     according to standard ISO10315:2013, using methanol in place of the     isopropanol mentioned in the standard. The chromatography material     used is the same as that used for the analysis of nicotine of the     tested sheet. 6 Replicates are performed for determining the     nicotine content in the aerosol.

The nicotine content in the reconstituted tobacco sheet is determined in the following way:

-   the nicotine content in the sheet tested is determined by gas     chromatography-FID detection analysis, with an Innowax gas     chromatography column (column dimensions: length 30 m; internal     diameter: 0.53 mm; film thickness 1 μm).

The results for the sheets tested are indicated in [Table 1] below.

These results demonstrate that the nicotine transfer rate of the reconstituted tobacco sheet 1 in accordance with the invention is significantly higher than the nicotine transfer rate of the tobacco sheets having a density of less than 0.6 g/cm³.

TABLE 1 Reconstituted tobacco sheet 1 in accordance with the  38% invention Reconstituted tobacco sheet not in accordance with the <30% invention

Organoleptic Properties

The tobacco sheet in accordance with the invention and a tobacco sheet not in accordance with the invention are cut into scaferlati (cut tobacco) and then smoked, one after the other, by an independent expert in a glo™ heating system.

According to the independent expert, all the aerosols formed during the smoking of the tobacco sheet in accordance with the invention have very satisfactory organoleptic properties, in particular the aerosol is not very bitter, not very irritant, not very aggressive and has a good round and balanced taste which is superior to the aerosols formed during the smoking of the tobacco sheet not in accordance with the invention. 

1. Reconstituted plant sheet comprising: a fibrous support comprising refined plant fibers, an aerosol-generating agent, and a plant extract, characterized in that the density of the reconstituted plant sheet is greater than or equal to 0.6 g/cm³, the total content by weight of solids of aerosol-generating agent is between 10% and 29%.
 2. Reconstituted plant sheet according to claim 1, the density of which is between 0.62 g/cm³ and 1.50 g/cm³.
 3. Reconstituted plant sheet according to claim 1, in which the plant is the tobacco plant.
 4. Reconstituted plant sheet according to claim 1, in which the total content by weight of solids of the plant extract is between 20% and 45%.
 5. Reconstituted plant sheet according to claim 1, in which the sum of the total content by weight of solids of plant extract and of the total content by weight of solids of aerosol-generating agent is between 40% and 70%.
 6. Reconstituted plant sheet according to claim 1, the thickness of which is between 100 μm and 450 μm.
 7. Reconstituted plant sheet according to claim 1, the basis weight of which is between 60 g/m² and 300 g/m².
 8. Reconstituted plant sheet according to claim 1, in which the aerosol-generating agent is sorbitol, glycerol, propylene glycol, triethylene glycol, lactic acid, glycerol diacetate, glyceryl triacetate, triethyl citrate, isopropyl myristate, or a mixture thereof.
 9. Process for producing a reconstituted plant sheet as defined in claim 1, comprising the following steps: a) passing the refined plant fibers through a papermaking machine so as to constitute a fibrous support, b) bringing an aerosol-generating agent and a plant extract into contact with the fibrous support so as to obtain a wet reconstituted plant sheet, and c) drying the wet reconstituted plant sheet.
 10. A heat but not burn device comprising reconstituted plant sheet as defined in claim 1, placed in association with in a heating device. 